It's been an eventful 1.5 months for boxing's best. Some of the fighters are new to this list of the top in the world regardless of weight — four, in fact. One of them is Guillermo Rigondeaux. But where? And who are the others? Read on to find out. And remember, the predominant standard is "quality wins, especially of recent vintage," with other standards — such as a simple assessment of an fighter's overall talent and form — secondary.

1. Floyd Mayweather, welterweight

Whatever you thought of Robert Guerrero's chances coming into this past weekend, Mayweather was impressive in dismantling a top-5 welterweight. It solidified his claim to the pound-for-pound throne, abetted by the inactivity of his consensus top threat, super middleweight champion Andre Ward. A September return for Floyd is a "maybe."

2. Juan Manuel Marquez, welterweight

We won't see Marquez again until September against Timothy Bradley in what figures as a nice match-up between experienced pro vs. talented youngster, both with fresh action credentials to boot. He's higher on this list than Ward because his best win (over Manny Pacquiao) is better than anything Ward has done, mostly.

3. Andre Ward, super middleweightt

Ward is due back in August, although hopefully it won't be against the winner of Sakio Bika-Marco Antonio Periban owing to alphabet belt politics. There can't be a soul outside of Bika and his family — not even the biggest Ward fans — who want to see a rematch of Ward-Bika, the foulingest match-up of the last few years.

4. Sergio Martinez, middleweight

OK, if you're going based on "current form," Martinez is hard to defend as a top-5 choice after looking so old and shaky against Martin Murray last month. But as close as the fight was, it wasn't some robbery that the decision went his way, so he'll instead be a very vulnerable #4 for a while.

5. Manny Pacquiao, welterweight

Pacquiao moves up thanks to previous #5 Nonito Donaire's loss to Guillermo Rigondeaux. It doesn't feel right to have him this high, but then, it's not like the Pac-Man's overall resume sucks, right? And he beat Timothy Bradley last year despite the official loss, don't forget. And lost to a very good Marquez.

6. Abner Mares, featherweight

Mares proved himself in yet another weight class, demonstrating featherweight power against Daniel Ponce De Leon, even if the stoppage was bunk. He leapfrogs Carl Froch, too. While Froch's highs are higher, the difference between the two men with brutal schedules is this: Froch has lost some of them, and Mares hasn't.

7. Carl Froch, super middleweight

That said, Froch could be right back above Mares and maybe even Pacquiao by the next update, since he's facing Mikkel Kessler later this month. It's one of the highlights of the summer schedule, even if it's a bummer that the HBO pairing of Kessler-Froch II with Jean Pascal-Lucian Bute is off due to a Bute injury.

8. Wladimir Klitschko, heavyweight

Ho-hum. The world's top heavyweight just beat another no-hoper last weekend, Francesco Pianeta, and his domination of substandard competition is getting very old. There's hope of things getting better if the Alexander Povetkin bout happens, but not much better, and based on the history of those two, it could still fall through.

9. Timothy Bradley, welterweight

Donaire's exit from the top 10, as well as the exit of Brian Viloria, gives Bradley an opening to return. The Transnational Boxing Rankings Board went with Guillermo Rigondeaux and left Donaire in after him, which is something I seriously considered myself.

10. Vitali Klitschko, heavyweight

Like his brother, Vitali deserves some credit for sustained dominance — even though he isn't doing anything these days, although it looks like he's going to continue his career and plans to face Bermane Stiverne next in a decent scrap. In the meantime, he's creeping up on one year of inactivity.

11. Guillermo Rigodeaux, junior featherweight

Putting Rigo higher is a-OK coming off the Donaire win last month, although top-5ish as ESPN has him is a bit much for my tastes. He's more than a one-win fighter, but without that one win he's not even in the top 20.

12. Nonito Donaire, junior featherweight

Donaire's overall resume protects him from dropping out of the list the way some others did with this update. But why Ring saw fit to have Donaire over Rigo even after Donaire lost to Rigo is baffling.

13. Bernard Hopkins, light heavyweight

Hopkins plans a quicker than usual ring return against Karo Murat in July, but that win won't do much for him; Murat is a top-10 light heavy, but beating him wouldn't prove much.

14. Roman Gonzalez, junior flyweight

With Juan Francisco Estrada beating Viloria in April, Gonzalez's own win over Estrada looks better than it did last year. As such, he leaps up a few spots.

15. Adrien Broner, lightweight

Broner could regain a spot on Gonzalez, though, depending on how he looks in a move up to welterweight in June against Paulie Malignaggi. Not that Malignaggi's a killer win, but a successful big weight leap would be impressive.

16. Chad Dawson, light heavyweight

Dawson, too, could be in line to restore some of his p4p stock by the next update, as he faces dangerous 168-pound puncher Adonis Stevenson in June.

17. Mikkel Kessler, super middleweight

See Froch, above. Kessler could be sniffing top-10 status if he pulls off a repeat of his years-ago defeat of Froch in what was a close but clear win.

18. Mikey Garcia, featherweight

Mikey is one of two Garcia's making his debut in the top 20, mainly on the strength of the Orlando Salido win and the eyeball test. He can solidify his standing with a win over Juan Manuel Lopez next month.

19. Danny Garcia, junior welterweight

This Garcia has established himself as the top 140-pounder in a top-heavy division, and while he doesn't pass the eyeball test the same as Mikey, he keeps beating solid fighters, like Zab Judah a couple weekends ago.

20. Saul Alvarez, junior middleweight

Austin Trout was in the #20 spot before Alvarez beat him last month, so it was a toss-up between Alvarez and previously ranked Robert Guerrero/Viloria or Estrada. The nod goes to Alvarez because he won his last fight and has a deeper resume than Estrada.

About Tim Starks

Tim is the founder of The Queensberry Rules and co-founder of The Transnational Boxing Rankings Board (http://www.tbrb.org). He lives in Washington, D.C. He has written for the Guardian, Economist, New Republic, Chicago Tribune and more.

CHAMPIONS

The Transnational Boxing Rankings Board champions are the true lineal champions of each division, like in earlier years of boxing when there was only one champion per division. For more on lineal champions vs. titleholders, click here.